The present disclosure relates to a laser sighting assembly for firearms and more particularly to a laser sighting assembly with laser range finding capability having a dual mode laser operable in both a sighting mode of operation and a range-finding mode of operation.
Laser sighting or targeting systems are known in the art for sighting a firearm on an intended target. Commonly, a laser sight is mounted on a firearm, such as an accessory mounting rail. When properly aligned with the barrel of the firearm, the laser will direct a beam to the target, which will appear as a dot on the target where the bullet will strike when the gun is fired.
The wavelength of the sighting laser may be in the visible region, typically red or green, e.g., for use in daylight conditions. Under nighttime or other low light conditions when a night vision system is used, an infrared (IR) sighting laser may be employed having a laser that emits a beam in the infrared region to which the night vision system is sensitive. For example, a sighting laser in the near-infrared region (NIR) (e.g., about 750-1400 nanometers, typically about 800-900 nm) would be viewable to a user wearing a conventional night vision system employing image intensifier (I2) technology.
Likewise, thermal imaging systems are known which are sensitive to the thermal infrared region, such as medium-wave infrared (MWIR) (e.g., 3,000-8,000 nm) or long-wave infrared (LWIR) (e.g., 8,000-15,000 nm). Thermal imaging technology has also been combined with conventional night vision technology. For example, enhanced vision systems (e.g., enhanced night vision goggles or ENVGs) are known which sense both NIR and thermal IR. A sighting laser in either the NIR region would be viewable by opposing forces equipped with either conventional night vision systems or with enhanced night vision systems.
Laser range finding devices are known which provide an accurate measurement of the distance to a target. In such units, a laser sends a beam toward a target and reflections of the beam from the target are detected by an optical receiver. The distance to the target is calculated based on the time-of-flight of the laser beam. The range finder typically emits a laser beam in a very short series of pulses, which may be encoded to assist the detector in recognizing the reflected signal.
Integrated systems that combine a laser sight (i.e., an aiming or pointing laser) and an optical range finder system are also known. Typically, such combined systems employ one or more separate lasers for sighting and a dedicated laser for range finding. For example, a combined laser sight may employ a sighting module having an infrared laser in the NIR region so as to be visible to persons using a night vision system based image intensifier technology (e.g., night vision goggles), and a range finding module using a dedicated laser in the short-wave infrared (SWIR) region rendering it invisible to the human eye, diurnal vision systems, as well as to night vision goggles and thermal (MWIR and LWIR) cameras or imagers. In this manner, such a system having separate sighting and range finding lasers are capable of remaining covert both to the human eye and to enemies having image intensifier and/or thermal imaging systems when used for range finding.
Prior art systems have not heretofore provided a laser sighting and range finding unit having single, dual function sighting and range finding laser for a number of reasons. First, it is preferable to employ a laser that is not detectable by conventional night vision or thermal imaging technology so that the range finding emissions do not inadvertently disclose the user's position to enemies. Second, the sighting laser is typically operated to produce a continuous beam, whereas the range finding laser is operated to provide a very brief pulse or series of pulses.
It is, therefore, the object of the present disclosure to provide an improved laser sighting and range finding unit which eliminates the need for a dedicated IR sighting laser and a separate, dedicated range finding laser, while remaining invisible to night vision and thermal imaging technology. By providing a single, dual-purpose IR laser, the cost and size of the unit may be reduced over comparable systems using separate sighting and range finding lasers.